Sandglass Star Pattern in Dart

import 'dart:io';
void main() {
  int i, j, k, n = 5;

  for (i = 0; i <= n - 1; i++) {
    for (j = 0; j < i; j++) {
      stdout.write(" ");
    }
    for (k = i; k <= n - 1; k++) {
      stdout.write("*" + " ");
    }
    stdout.writeln("");
  }
  for (i = n - 1; i >= 0; i--) {
    for (j = 0; j < i; j++) {
      stdout.write(" ");
    }
    for (k = i; k <= n - 1; k++) {
      stdout.write("*" + " ");
    }
    stdout.writeln("");
  }
}

OUTPUT

                                       *   *   *   *   * 
                                         *   *   *   * 
                                           *   *   * 
                                             *   * 
                                               * 
                                             *   * 
                                           *   *   * 
                                         *   *   *   * 
                                       *   *   *   *    *